Performance Debugging and Tuning using an Instruction-Set Simulator

Instruction-set simulators allow programmers a detailed level of insight into, and control over, the execution of a program, including parallel programs and operating systems. In principle, instruction set simulation can model any target computer and gather any statistic. Furthermore, such simulators are usually portable, independent of compiler tools, and deterministic-allowing bugs to be recreated or measurements repeated. Though often viewed as being too slow for use as a general programming tool, in the last several years their performance has improved considerably. We describe SIMICS, an instruction set simulator of SPARC-based multiprocessors developed at SICS, in its rôle as a general programming tool. We discuss some of the benefits of using a tool such as SIMICS to support various tasks in software engineering, including debugging, testing, analysis, and performance tuning. We present in some detail two test cases, where we've used SimICS to support analysis and performance tuning of two applications, Penny and EQNTOTT. This work resulted in improved parallelism in, and understanding of, Penny, as well as a performance improvement for EQNTOTT of over a magnitude. We also present some early work on analyzing SPARC/Linux, demonstrating the ability of tools like SimICS to analyze operating systems

A Design and Implementation of the Extended Andorra Model

Logic programming provides a high-level view of programming, giving implementers a vast latitude into what techniques to explore to achieve the best performance for logic programs. Towards obtaining maximum performance, one of the holy grails of logic programming has been to design computational models that could be executed efficiently and that would allow both for a reduction of the search space and for exploiting all the available parallelism in the application. These goals have motivated the design of the Extended Andorra Model, a model where goals that do not constrain non-deterministic goals can execute first. In this work we present and evaluate the Basic design for Extended Andorra Model (BEAM), a system that builds upon David H. D. Warren's original EAM with Implicit Control. We provide a complete description and implementation of the BEAM System as a set of rewrite and control rules. We present the major data structures and execution algorithms that are required for efficient execution, and evaluate system performance. A detailed performance study of our system is included. Our results show that the system achieves acceptable base performance, and that a number of applications benefit from the advanced search inherent to the EAM.Comment: 43 pages, To appear in Theory and Practice of Logic Programming (TPLP

Performance of Sparse Binding Arrays for Or-Parallelism

One important problem in the design of novel logic programming systems is the support of several forms of implicit parallelism. A new binding model, the Sparse Binding Array (SBA), has been proposed for the efficient and simplified integration of Independent-And, Determinate-And and Or-parallelism. In this paper we report on the use of this model for pure Or-parallelism. The work discusses the major implementation issues in supporting this binding model for pure Or-parallelism. We show that an implementation based on this Binding model is more efficient then the original Aurora using tbe traditional Binding Array model [16]. Moreover, we explain how the notion of a variable level can be used to reduce overheads of the Orparallel system. Our results in supporting pure or-parallelism show that the approach is very promissing for combined paralell systems.</jats:p

An abstract model for parallel execution of prolog

Logic programming has been used in a broad range of fields, from artifficial intelligence applications to general purpose applications, with great success. Through its declarative semantics, by making use of logical conjunctions and disjunctions, logic programming languages present two types of implicit parallelism: and-parallelism and or-parallelism. This thesis focuses mainly in Prolog as a logic programming language, bringing out an abstract model for parallel execution of Prolog programs, leveraging the Extended Andorra Model (EAM) proposed by David H.D. Warren, which exploits the implicit parallelism in the programming language. A meta-compiler implementation for an intermediate language for the proposed model is also presented. This work also presents a survey on the state of the art relating to implemented Prolog compilers, either sequential or parallel, along with a walk-through of the current parallel programming frameworks. The main used model for Prolog compiler implementation, the Warren Abstract Machine (WAM) is also analyzed, as well as the WAM’s successor for supporting parallelism, the EAM; Sumário: Um Modelo Abstracto para Execução Paralela de Prolog A programação em lógica tem sido utilizada em diversas áreas, desde aplicações de inteligência artificial até aplicações de uso genérico, com grande sucesso. Pela sua semântica declarativa, fazendo uso de conjunções e disjunções lógicas, as linguagens de programação em lógica possuem dois tipos de paralelismo implícito: ou-paralelismo e e-paralelismo. Esta tese foca-se em particular no Prolog como linguagem de programação em lógica, apresentando um modelo abstracto para a execução paralela de programas em Prolog, partindo do Extended Andorra Model (EAM) proposto por David H.D. Warren, que tira partido do paralelismo implícito na linguagem. É apresentada uma implementação de um meta-compilador para uma linguagem intermédia para o modelo proposto. É feita uma revisão sobre o estado da arte em termos de implementações sequenciais e paralelas de compiladores de Prolog, em conjunto com uma visita pelas linguagens para implementação de sistemas paralelos. É feita uma análise ao modelo principal para implementação de compiladores de Prolog, a Warren Abstract Machine (WAM) e da sua evolução para suportar paralelismo, a EAM

A note on retrodiction and machine evolution

Biomolecular communication demands that interactions between parts of a molecular system act as scaffolds for message transmission. It also requires an evolving and organized system of signs - a communicative agency - for creating and transmitting meaning. Here I explore the need to dissect biomolecular communication with retrodiction approaches that make claims about the past given information that is available in the present. While the passage of time restricts the explanatory power of retrodiction, the use of molecular structure in biology offsets information erosion. This allows description of the gradual evolutionary rise of structural and functional innovations in RNA and proteins. The resulting chronologies can also describe the gradual rise of molecular machines of increasing complexity and computation capabilities. For example, the accretion of rRNA substructures and ribosomal proteins can be traced in time and placed within a geological timescale. Phylogenetic, algorithmic and theoretical-inspired accretion models can be reconciled into a congruent evolutionary model. Remarkably, the time of origin of enzymes, functional RNA, non-ribosomal peptide synthetase (NRPS) complexes, and ribosomes suggest they gradually climbed Chomsky's hierarchy of formal grammars, supporting the gradual complexification of machines and communication in molecular biology. Future retrodiction approaches and in-depth exploration of theoretical models of computation will need to confirm such evolutionary progression.Comment: 7 pages, 1 figur

Identifying Factors Impacting the Intention to Use Videos of Authentic Patient Encounters by EMS Educators

The cornerstones of prehospital provider education include didactic instruction, psychomotor skills training, and hospital and ambulance clinical rotations. Increasing enrollment in healthcare education programs, limited clinical opportunities, and an increasingly technologically savvy student body are compelling educators to pursue supplementary techniques for teaching and learning. Although high fidelity simulators are becoming increasingly commonplace, other educational technologies are less widely adopted. Concomitantly, little research has been conducted exploring rationale and motivating factors for adoption and utilization of technology by EMS educators. Videos of authentic patient encounters recorded in clinical settings (VAPE) have the potential to provide students an opportunity to learn applicable content in a safe and controlled learning environment. The integration of various educational video modalities into curriculum has been shown to increase student engagement and motivation in other settings but has not been studied within the prehospital education environment. This research is designed to investigate the behavioral intention and use of VAPE by EMS program faculty and staff. A cross-sectional survey design of an extended version of the Technology Adoption Model will be employed to collect participant data. The TAM model was extended to include prior experience, technological competency, social norms, and characteristics of personality as determined by the Five Factor Model (FFM). Study participants included academic professionals who are currently working with or teaching for an accredited prehospital EMS education program and are involved in the design or instruction of curriculum. An online survey assessing attitude, prior experience, technological competency, social norms, and personality were sent to faculty and staff of currently accredited EMS education programs. Participants received the questionnaire electronically and had access to complete the survey at their convenience. A total of 148 completed surveys were included in the analysis. The sample was largely male (71.1%) with an average age of 48.9 years, with a main personality trait of conscientiousness (31%). Factor analysis resulted in the inclusion of 7 factors; perceptions of utility, stability, agreeableness, extraversion, conscientiousness, technological competency, and prior experience. A path analysis determined Factor 1: Perceptions of Utility had a strong positive impact on intention to use VAPE by EMS educators. Thematic analysis identified VAPE as a means to meet the educational needs of faculty and students and improve student learning. However, challenges to adoption were also identified and included cost, as well as administrative and technical support

Visualization of AI Systems in Virtual Reality: A Comprehensive Review

This study provides a comprehensive review of the utilization of Virtual Reality (VR) for visualizing Artificial Intelligence (AI) systems, drawing on 18 selected studies. The results illuminate a complex interplay of tools, methods, and approaches, notably the prominence of VR engines like Unreal Engine and Unity. However, despite these tools, a universal solution for effective AI visualization remains elusive, reflecting the unique strengths and limitations of each technique. We observed the application of VR for AI visualization across multiple domains, despite challenges such as high data complexity and cognitive load. Moreover, it briefly discusses the emerging ethical considerations pertaining to the broad integration of these technologies. Despite these challenges, the field shows significant potential, emphasizing the need for dedicated research efforts to unlock the full potential of these immersive technologies. This review, therefore, outlines a roadmap for future research, encouraging innovation in visualization techniques, addressing identified challenges, and considering the ethical implications of VR and AI convergence.Comment: 19 page

Programming constraint services

This thesis presents design, application, implementation, and evaluation of computation spaces as abstractions for programming constraint services at a high level. Spaces are seamlessly integrated into a concurrent programming language and make constraintbased computations compatible with concurrency through encapsulation. Spaces are applied to search and combinators as essential constraint services. State-of-the-art and new search engines such as visual interactive search and parallel search are covered. Search is expressive and concurrency-compatible by using copying rather than trailing. Search is space and time efficient by using recomputation. Composable combinators, also known as deep-guard combinators, stress the control facilities and concurrency integration of spaces. The implementation of spaces comes as an orthogonal extension to the implementation of the underlying programming language. The resulting implementation is shown to be competitive with existing constraint programming systems.Diese Dissertation beschreibt Entwurf, Verwendung, Implementierung und Evaluierung von Computation Spaces für die Programmierung von Constraintdiensten. Spaces werden in eine nebenläufige Programmiersprache integriert. Sie fungieren als Kapseln für Berechnungen mit Constraints. Dadurch wird die Kompatibilität zu nebenläufigen Berechnungen gewährleistet. Suche und Kombinatoren sind zentrale Constraintdienste, die mit Spaces programmiert werden. Es werden sowohl übliche, als auch vollkommen neue Suchmaschinen, wie zum Beispiel interaktive Suche und parallele Suche, vorgestellt. Durch Kopieren wird Suche ausdrucksstark und kompatibel mit Nebenläufigkeit. Durch Wiederberechnung wird Suche effizient hinsichtlich Speicherbedarf und Laufzeit. Kombinatoren, die ineinander geschachtelt werden können (so genannte deep-guard Kombinatoren), verdeutlichen die Kontrollmöglichkeiten von Spaces. Die Implementierung von Spaces erfolgt als orthogonale Erweiterung einer Implementierung für die zugrundeliegende Programmiersprache. Das Ergebnis ist konkurrenzfähig zu existierenden Constraintprogrammiersystemen